Two-shaft hinge with rotation limiting mechanism

ABSTRACT

In a portable telephone, laptop personal computer or remote control in which reduced size, reduced weight and new functionality are required, to provide a two-shaft hinge component equipped with a rotation limiting mechanism in which a construction is adopted that makes possible a rotation limiting mechanism with increased durability, reduced size and lighter weight.  
     A torque unit is constituted by a fixed cam and a rotary cam being in coaxial abutment with a rotary shaft  2  and an opening/closing shaft  3,  in a hinge of two-shaft construction in which a rotary shaft  2  passes through an opening/closing shaft  3,  sliding frictional torque and a click action being generated during rotation and opening/closing operation by an abutting cam surface. The torque unit is constructed independently on the rotary shaft and the opening/closing shaft and, in addition, there is provided a rotation limiting mechanism whereby the rotary action of the rotary shaft is subjected to limitation in accordance with the opening/closing angle of the opening/closing shaft. With the two-shaft hinge according to the present invention, reduction in size and weight is achieved by reducing the number of components, a stable torque and click action are generated, durability is improved and additional space is secured by a concentrated arrangement of the components.

TECHNICAL FIELD

The present invention relates to a two-shaft type hinge component thatis employed in the fold-up/rotary mechanism of small electronic devicessuch as portable telephones, laptop personal computers, electronicnotebooks, DVD monitors or remote controllers.

BACKGROUND ART

The frictional torque generating mechanism for the opening/closing shaftand rotary shaft of a prior art two-shaft hinge comprised in practicallyall cases a mechanism in which a plate member was coiled onto a shaft ora mechanism in which rotary frictional torque was generated by aconstruction in which pressure was applied by a dish spring.

FIG. 16 shows an example of a prior art two-shaft hinge shown inJapanese Patent Publication No. 2002-155923. In this hinge, a platespring 54 formed in corrugated fashion and brackets 56 are fixed to theshaft at both ends of a press-formed opening/closing shaft 52 by meansof a fixing flange 53. Also, a rotary shaft 57 is arranged penetratingto the middle of the opening/closing shaft 52; rotary frictional torqueis generated by the method of pressure contact with a plate spring 59.

With the prior art hinge product, due to the fact that no rotary anglestop mechanism of the opening/closing shaft to limit rotation of therotary shaft was provided and, in addition, due to the method ofgenerating torque by pressing the friction plate into contact using therepulsive force of the dish spring, there were problems of looseness,rattling or poor durability caused by such as wear of the frictionalplates 52, 56 or deformation (weakening) of the plate spring 54. Torquefluctuation or deterioration of durability produced by secular changesnot only impairs the quality of the device but may also cause failure.Accordingly, as considered in the above reference, in recent two-shafthinges, compared with prior art products, closer attention is paid toease of operation and feeling during opening/closing or rotating, aswell as the mechanism for limiting the angle of rotation or opening andclosure, and maintenance of a stable torque value, high durability andalso reduction in size and weight are strongly demanded.

DISCLOSURE OF THE INVENTION

The problem that the present invention is intended to solve is toprovide a two-shaft hinge component whereby durability, reduction insize and reduction in weight can be achieved in portable telephones ornotebook type personal computers in which smaller size and lighterweight are demanded.

The present invention is constituted as following (1)-(9).

(1) A two-shaft hinge that has a rotary shaft and an opening/closingshaft and enables a rotational action and an opening/closing action,wherein,

the rotary shaft is inserted into the opening/closing shaft by fittingthe rotary shaft into a through hole provided in a vertical directionwith respect to a longitudinal direction of the opening/closing shaft;

a fixed cam, a rotary cam and a spring are inserted into each of therotary shaft and the opening/closing shaft;

the fixed cam and the rotary cam abut by the spring force;

the abutting cams and the spring compose a torque unit thatindependently generates a sliding frictional torque at the rotationalaction and the opening/closing action;

a rotational action of the rotary shaft is limited by a rotationlimiting mechanism depending on a rotational angle of theopening/closing shaft; and

the rotation limiting mechanism limits the action by abutting faces tolimit at two locations provided between the rotary shaft and theopening/closing shaft.

(2) A two-shaft hinge equipped a rotation limiting mechanism that has arotary shaft and an opening/closing shaft and enables a rotationalaction and an opening/closing action, wherein,

the rotary shaft is inserted into the opening/closing shaft by fittingthe rotary shaft into a through hole provided in a vertical directionwith respect to a longitudinal direction of the opening/closing shaft;

a fixed cam, a rotary cam and a spring are inserted into each of therotary shaft and the opening/closing shaft;

the fixed cam and the rotary cam abut by the spring force;

the abutting cams and the spring compose a torque unit thatindependently generates a sliding frictional torque at the rotationalaction and the opening/closing action;

a rotational action of the rotary shaft is limited by a rotationlimiting mechanism depending on a rotational angle of theopening/closing shaft; and

the rotation limiting mechanism limits the action by abutting faces tolimit at a single location provided between the rotary shaft and theopening/closing shaft.

(3) A two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein, a part of therotary shaft has a cross-section which has a long diameter and a shortdiameter, and a width of an aperture thereof has a width such as toobstruct rotation of the rotary shaft while abutting on this crosssection, depending on an angle of opening/closure of the opening/closingshaft and a width such as to make rotation of the rotary shaft possible,or, a rotation limiting groove or a rotation limiting plate is formed inan area on a side of a drive body.

(4) A two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein, theopening/closing torque mechanism of the opening/closing shaft isarranged concentrated on one side, either left or right of an axialdirection with respect to the shaft hole of the opening/closing shaftthrough which the rotary shaft passes, while the other side thereofconstitutes a space region for wiring or the like.

(5) A-two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein, theopening/closing torque mechanism of the opening/closing shaft comprisesunits at two or more locations, said units generating a frictionaltorque by a repulsive force of the spring at the abutting cam faces byabutting the rotary cam capable of rotation and the fixed cam that ismovable in an axial direction and rotates in unison with theopening/closing shaft and engaging the fixed cam and the rotary camthrough the opening/closing shaft.

(6) A two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein a range of rotationof the rotary shaft and the opening/closing shaft is limited byproviding a stop mechanism for limiting the rotation and opening/closingangle of the rotary shaft and the opening/closing shaft.

(7) A two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein, in order togenerate a click action at a specified position during the rotationalaction and the opening/closing action of the rotary shaft and theopening/closing shaft, a mechanism that generates a click action isprovided by providing a projection and recess on the fixed cam and therotary cam constituted on the shafts for generating torque and abutmentof the projection and recess of the fixed and the rotary cam, or byadding an abutment location of a projection and recess on the rotaryshaft and the opening/closing shaft.

(8) A two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein the rotary shaftand the opening/closing shaft respectively have a cross-section formedto be a cross-section other than circular at a sliding location of thefixed cam so that the fixed cam integrally rotates with the shafts whilesliding.

(9) A two-shaft hinge equipped with a rotation limiting mechanismaccording to the above-mentioned (1) or (2), wherein a bracket componentis added on the opening/closing shaft so as to dispose and fix thetwo-shaft hinge to an outer frame, and the hinge is fixed by thebracket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the constitution of components illustrating anembodiment of the invention according to claim 1 and claim 2.

FIG. 2 is a front view showing an embodiment of the invention accordingto claim 1.

FIG. 3 shows an embodiment of the invention according to claim 2 andclaim 4, (a) being a front view, (b) being a right side view and (c)being an example of rotary operation.

FIG. 4 is a bottom view showing an embodiment of the invention accordingto claim 2.

FIG. 5 is a rear view showing an embodiment of the present inventionaccording to claim 2.

FIG. 6 shows an embodiment of the invention according to claim 5 andclaim 6, (a) being an internal front view and (b) being a bottom viewand (c) being a right side view.

FIG. 7 shows an embodiment of the invention according to claim 8, (a)being a front view of the opening/closing shaft, (b) being a plan viewof the opening/closing shaft, (c) being a cross-sectional view of therotation limiting section, (d) being a front view of the rotary shaftand (e) being a plan view of the rotary shaft.

FIG. 8 is an example of an embodiment of a rotation limiting plate(groove) employed in the invention according to claim 3, (a) being aleft side view, (b) being a cross-sectional view, (c) being a right sideview and (d) being a plan view.

FIG. 9 is a example of an embodiment of the operation of the rotationlimiting mechanism employed in the invention according to claim 3, (a)being a plan view of the first stage thereof, (b) being a plan view ofthe second stage thereof and (c) being a plan view of a third stagethereof.

FIG. 10 is a model showing an embodiment according to claim 1, claim 2and claim 3, (a) showing the two-location limiting mechanism, (b)showing the single-location limiting mechanism and (c) showing anapplication of the two-location limiting mechanism.

FIG. 11 shows an embodiment of a rotary cam employed in the inventionaccording to claim 7, (a) being a front view, (b) being a side view and(c) being a rear view.

FIG. 12 shows an embodiment of a fixed cam employed in the inventionaccording claim 7, (a) being a front view, (b) being a side view and (c)being a rear view.

FIG. 13 shows an embodiment of a rotary cam employed in the inventionaccording to claim 7, (a) being a front view, (b) being a side view and(c) being a rear view.

FIG. 14 shows an embodiment of a fixed cam employed in the inventionaccording to claim 7, (a) being a front view, (b) being a side view and(c) being a rear view.

FIG. 15 is a front view showing an embodiment of the invention accordingto claim 9.

FIG. 16 is a front view showing a prior art example.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention are described below with referenceto the drawings.

FIG. 1 shows the parts compose an example of an embodiment of thetwo-shaft hinge equipped with a rotation-limiting mechanism according toclaim 1. From the top of the Figure, the rotary system, which is on therotary shaft of the two shafts, comprises the following: a bracket 1 onwhich the liquid-crystal monitor is mounted, a rotary shaft 2, arotation stop plate 4 with a screw-hole, rotary and fixed cams 5, a dishspring 6, a rotary locking plate 7 and a stop ring 8 for the rotaryshaft.

Also, from the left-hand side of the Figure, the opening/closing system,which is on the opening/closing shaft namely the other shaft, comprisesthe following components: a stop ring 15 for the opening/closing shaft,a corrugated plate spring 16, a left rotation limiting plate 9, anopening/closing shaft 3, a right rotation limiting plate 9, a rotary andfixed cam 10 for the opening/closing shaft, a coil spring 11, a fixedand rotary cam 12, an opening/closing shaft casing 13, a fixed frictionplate 14, and a stop ring 15 for the opening/closing shaft.

In the bracket 1, ribs 1-2, 1-3 equipped with screw-holes for mountingof for example a liquid-crystal monitor are provided by flat platepressing and a hole 1-4 with which the swaging end 2-1 of the rotaryshaft is fitted and fixed by swaging is provided. On the rotary shaft 2,there are provided a swaging end 2-1 that is formed with a square shape,a shaft 2-2 having circular cross section on which is wound flat panelconnector (FPC) wire, a rotation limiting plate 2-3 having oval-shapedcross section for limiting rotation, a shaft 2-4 having a square columncross section with D cut or radiussed corners, and a stop ring groove2-5. A screw-hole 4-2 for fixing such as wiring and a stop plate section4-1 used by assembling the rotary locking plate 7 on an L-shaped pressedmember to limit the angle of rotation thereof are provided on therotation stop plate 4 with a screw-hole. The cam set 5 for the rotaryshaft comprise a rotary cam 5-1 having a recess at its surface androtating in unison with the opening/closing shaft, and a fixed cam 5-2having a projection at its surface and rotating in unison with therotary shaft. The basic form of the rotary locking plate 7 is seen byreferring the FIG. 4, which shows the assembled two-shaft hinge of theFIG. 1 from underneath. The rotary locking plate 7 has projections 7-1and 7-2, and, the combination of the projections and a stop 4-1 of thestop plate 4 restricts the angle of rotation (This rotational anglelimitation is called as a stop mechanism in order to distinguish fromthe rotation limiting mechanism in claims) aside from the rotationlimiting mechanism as described later. The rotational angle restrictionmechanism of the stop mechanism will be explained later.

The assembly of the two-shaft hinge will be explained, to start with thedescription of the opening/closing shaft. The left-hand side portion ofFIG. 1 is assembled by following: the opening/closing shaft 3 isinserted into the left rotation limiting plate 9 and corrugated platespring 16, and the stop ring 15 is pressed into the stop ring groove3-7. In the right hand side, the opening/closing torque unit isconstituted by following: a joining face 9-5 of the right rotationlimiting plate 9 is fitted and inserted into an opening/closing limitingplate joining face 3-1 of the opening/closing shaft 3 and theopening/closing shaft is inserted in a rotary cam 10-1 for theopening/closing shaft, a fixed cam 10-2 for the opening/closing shaft, acoil spring 11, and a further set of fixed cam 12-2 and rotary cam 12-1.Furthermore, the opening/closing shaft is inserted into the shaft hole13-1 of the opening/closing shaft casing 13 and the fixed frictionalplate 14, and, the stop ring 15 is pressed into the opening/closingshaft groove 3-7, with the spring 11 still compressed in the axialdirection, and with pressing on the bottom plate 13-2 of the casing orthe fixed frictional plate 14 by use of a jig or the like. In this case,the torque unit is composed of the shaft, the cam set and the spring,and is a section that generates a sliding frictional torque or a clickaction (pull-in action). Moreover, the rotation limiting plate 9 amongthe above is used in the rotation limiting mechanism of the presentinvention and the mechanism will be explained in detail below.

Next, the rotary shaft will be explained. As for the rotary shaft, theend 2-1 for swaging of the opening/closing shaft 2 is inserted into thebracket hole 1-4 and the bracket 1 and the shaft 2 are fixed by swaging.The shaft section 2-4 of the rotary shaft is inserted into a rotaryshaft through-hole 3-4 of the opening/closing shaft 3, thereby, it willbe rotatable through 360° in a condition with the flat face 3-3 of theopening/closing shaft and the limiting face 2-3 of the rotary shaft inabutment. The assembly of the rotary torque unit and the stop mechanismis achieved as follows: the remaining rotary shaft section 2-4 throughwhich the opening/closing shaft 3 has passed is inserted into therotation stop plate 4; it is brought tightly into contact with a flatportion 3-5 of the opening/closing shaft; thereafter, the rotary cam 5-1for the rotary shaft, fixed cam 5-2, dish spring 6 and rotary lockingplate 7 are assembled; and finally the stop ring 8 is pressed into therotary shaft with the dish spring compressed.

FIG. 2 is a front view of a completed product of the two-shaft hingeaccording to the first aspect of the present invention provided with arotation limiting mechanism obtained by assembly of the componentsillustrated in FIG. 1 as described above. The two shaft hinge of FIG. 2shows the appearance of the constitution of the rotation limitingmechanism to limit the rotational action of the rotary shaft 2 dependingon the opening/closure angle of the opening/closing shaft 3 by abuttingthe oval-shaped rotation limiting plate 2-3 and the rotation limitingplate 9 at two locations on the left and the right. The abutting facesof the two parts correspond to the abutting faces to limit at twolocations of the present invention and the rotation limiting mechanismachieved thereby is a remarkable feature of the present invention. Itcan be seen from the component constructional view of FIG. 1 and theproduct of FIG. 2 that the two rotation limiting plates (grooves) 9provided on the opening/closing shaft 3 are brought into pressurecontact with the limiting plate joining face 3-1 by the repulsive forceof the spring 11, 15 against the stop ring 15 arranged at the shaft end.In FIG. 2, the rotation limiting plates 9 and the casing 13 areassembled by means of fitting grooves so as to suppress rattling duringrotation. The casing 13 is of D shape or oval shape in the cross sectionby cutting a part of circle and can be fixed so that there is norattling by the method of insertion fitting when mounted and fixed onthe external frame. Also, although not shown in the drawing, therotation limiting plates (grooves) 9 arranged on the left and right arecoupled by a linking plate or the like.

FIG. 3(a) shows an example of the second aspect of the present inventionin which the rotation limiting mechanism effects limitation of rotationof the rotary shaft by the abutting faces at a single location, incontrast with a method in which such rotational limitation of the rotaryshaft is implemented by the abutting faces of the rotation limitingplate 9 at two locations of the left and right shown in FIG. 2.

Also, FIG. 2 and FIG. 3(a) show an example in which the torque unit ofthe opening/closing shaft of the forth aspect of the present invention,which is a combination of a cam set and a spring, is arrangedconcentrated on one side, either the left or the right side, in theaxial direction with respect to the shaft hole of the opening/closingshaft, through which the rotary shaft passes, while the other sidethereof provides a space region for example for wiring.

FIG. 3(b) is a right side view of (a). This shows that the stop ring 15that is a c-shaped ring is pressed and fixed into a groove 3-7 for thestop ring (see FIG. 1) at the end of the opening/closing shaft,furthermore, that the shaft cross-sectional face 3-2 of theopening/closing shaft 3 is of special cross section shape i.e.oval-shaped. It also shows that the opening/closing shaft 3 is preventedfrom further anti-clockwise rotation by the leading end 4-1 of therotation stop plate 4, which is formed in L shape, being in contact witha projection 7-1 of a rotary locking plate 7 fixed to the rotary shaft2, as shown in the bottom view of FIG. 4. This is the stop mechanism inwhich the leading end 4-1 limits the rotation of the rotary shaft 2 byengaging the rotation stop plate 4 and the rotation locking plate 7.

FIG. 3(c) is an example showing the condition in which theopening/closing shaft has rotated as far as an angle of 150°. FIG. 3(b)shows a condition in which the opening/closing shaft has rotated by 90°;in the case of a portable telephone that folds in two, this condition isa position in which the telephone is opened perpendicularly from acondition in which the liquid-crystal screen for the monitor is closed.Also, (c) shows a condition in which the telephone is further opened by60° from FIG. 3(b) i.e. it is the usual communication-ready position ofa portable telephone equipped with a speaker and a microphone. FIG. 3(c)shows a condition in which the opening/closing shaft is opened by 150°.In this case, since no stop for limiting the angle of rotation isprovided on the opening/closing shaft, clockwise rotation through 360°is possible. A cross-section of the opening/closing shaft casing 13(hatched portion) presents an oval shape with both ends of the circlecut off.

FIG. 4 is an example showing the stop mechanism for rotation around therotary shaft according to the sixth aspect of the present invention,being a view showing the bottom face of the two-shaft hinge. Like FIG. 2and FIG. 3, FIG. 4 shows the case where the bracket 1 and theopening/closing shaft 3 are positioned in parallel, showing thecondition in which the leading end 4-1 of the rotation stop plate andthe projection 7-1 of the rotary locking plate are in contact. In theFIG. 4, anti-clockwise rotation of the rotary shaft 2 is restricted,rotation being only possible by about 180° in the clockwise direction;the region in which rotation is possible is between the projections 7-1and 7-2 of the rotation locking plate 7.

FIG. 5 is a rear view of FIG. 3(a). As for the rotation limitingmechanism, the Figure shows the condition in which the rotation limitingplates (grooves) 9 that are assembled with the opening/closing shaftabut the limiting plate 2-3 of the rotary shaft. In the case of thisFigure, it can also be seen that the rotation limiting plates (grooves)9 are cylindrical, being of a shape in which the abuttingcircumferential faces thereof are recessed in a partially arcuatecondition namely sloped condition.

FIG. 6 shows an example of a torque unit of the opening/closing shaftaccording to the fifth aspect of the present invention. Theopening/closing torque unit arranged on the opening/closing shaft 3-2comprises rotary cam 10-1, rotary cam 12-1 and fixed cam 10-2, fixed cam12-2 and a coil spring 11 that generates a sliding frictional torque anda click action (pull-in action) by pressure contact with the cams, onthe opening/closing shaft 3-2. Regarding the shape of the rotary andfixed cams that are here employed, these are ring-shaped, as shown inFIGS. 11 and 12, with projections and recesses formed on the surfacethereof on one side, the projections and recessed faces being abutmentfaces. FIGS. 6(a) and (b) show the case where the projections andrecesses of both of the cam sets 10, 12 are fitted together and a spring11 that supplies repulsive force is extended in the axial direction.Various cam shapes may be selected for use from conditions such as thethickness, the presence or absence of projections or recesses, and theirposition of arrangement and height, depending on the required torquevalue and the click angle. Moreover, it can be seen that theopening/closing shafts 3-2, 3-8 on which the rotary and fixed cams arefitted are shafts of special cross-sectional shape, their shaftdiameters (sizes) being different in FIG. 6(a), which is a front view,from FIG. 6(b), which is a bottom view thereof.

The components that rotate in unison with the opening/closing shaft 3-2in FIGS. 6(a) and (b) are the fixed cams 10-2, 12-2, the spring 11, thefixed frictional plate 14 and the stop ring 15. Also, the componentsthat rotate in unison with the opening/closing shaft casing 13, whichplays the role of extracting the opening/closing torque to the outside,are the rotary cams 10-1, 12-1 that rotate around the opening/closingshaft 3-2, the casing bottom plate 13-2 and the rotation limiting plates9.

FIG. 6(c) shows an example of the sixth aspect of the present inventionin which the rotation stop mechanism that limits the rotational angle ofthe opening/closing shaft is additionally provided. A projection 13-3 isprovided at the outer periphery of the casing bottom plate 13-2, then,the additional stop mechanism limits the rotational angle of theopening/closing shaft by abutting this projection against a projection14-1 of the fixed frictional plate 14 that rotates in unison with theopening/closing shaft 3. FIG. 6(c) shows that when the opening/closingshaft 3 rotates further in the anti-clockwise direction the projections13-3 and 14-1 come into abutment, so that further rotation is prevented.Since the fixed frictional plate 14 is provided to rotate in unison withthe opening/closing shaft 3, the shape of the shaft hole 14-2 and theend 3-7 of the opening/closing shaft are made oval-shaped, assemblybeing effected by pressing in, so as to prevent rattling.

FIG. 7 is an example of the eighth aspect of the present invention, thetwo shaft hinge, and the opening/closing shafts were drawn in (a) and(b) and the rotary shafts were drawn in (c) and (d). In the Figure,shafts are formed with a cross-sectional shape whose axial cross-sectionat the location where the fixed cam is positioned is processed otherthan circle. First of all, the cross-sections of the shafts at theportions 3-2, 3-8 of FIGS. 7(a) and (b) are oval-shaped, with parts ofthe circle cut away. It can be seen that this cross-section is a shapewhich makes it possible to rotate integrally with the shaft and to slidein the axial direction when the shaft is inserted into the shaft holes10-4, 12-4 of the fixed cams shown in FIG. 12. Similarly, the rotaryshaft (c) and (d) at the location 2-4 are of square pillar shape withradiussed corners, as shown on the right of (d), is inserted into thefixed cams shown in FIG. 14 and assembled. The portion 2-4 of this shaftand the portion 5-6 of the cam hole are manufactured with dimensionssuch as to enable the cam to integrally rotate with the shaft but withthe cam allowed to slide in the axial direction.

In order to prevent rattling of the rotary shaft and to maintain stablerotation, it is desirable that the upper surface 3-3 and the lowersurface 3-5 of the through-hole 3-4 of the opening/closing shaft 3should be flat. Steps 3-9 provided on the shaft and the projection 3-1maintain stable assembly and rotation of the limiting plates 9 byabutting on the shaft hole 9-3 and bottom 9-5 of the rotation limitingplates (grooves) 9 shown in FIG. 8. Here, a flat portion 3-8 of theopening/closing shaft 3 to be inserted into the fixed cam ismanufactured inclined with respect to the axial center direction of thethrough-shaft (the face including the diameter of the rotary shaftinserted) from FIG. 7(b). The shaft end 3-7 of FIG. 6(c) shows anexample of the assembly thereof. The purpose of making the insertedportions 3-8 of the shaft into these cams 10, 12 inclined, or of makingthe shaft hole 10-4, 12-4 of the fixed cams inclined, which is expectedto show the same effect, is both in order to strengthen the rotary clickfeeling of the opening/closing shaft and to prevent rattling.

The rotation limiting plate 2-3 on the rotary shaft depicted in FIGS.7(c), (d) and (e) is of a cross-sectional shape having a long diameterand a short diameter obtained by cutting off portions of a cylinder toproduce an oval shape having parallel sides. Limitation of rotation iseffected by the outer periphery of this cross-sectional shape abuttingthe rotation limiting plates (grooves) 9. Although, in this case, theshaft rotation limiting plate 2-3 was manufactured as a unitary memberfrom a round rod, it would also be possible to manufacture only limitingplates 2-3 for example by press forming and then to press these onto theshaft or to assemble a plurality of limiting plates 2-3 in order toprovide a complex limiting action.

FIG. 8 shows the shape of a rotation limiting plate (groove) 9 that isemployed in the rotation limiting mechanism, disposed on theopening/closing shaft and used in the third aspect of the presentinvention. (a) shows a location at which the casing 13 is coupled;projections 9-6 are provided at two locations to effect coupling. (b)shows the cross section of the limiting plate (groove) 9; a couplingprojection 9-6, a projection 9-1 on the cylindrical periphery of thelimiting plate, a bottom (groove) section 9-2 of the cylindricalperiphery and a slope starting section 9-4 are shown. In (c), theprojection 9-1 is drawn in white, whereas the slope 9-4 and groovesection 9-2 are depicted in black. A hole 9-3 and flat section 9-5 areassembled by fitting in with the respective steps 3-9 and 3-1 (see FIG.7) of the opening/closing shaft. (d) is a side view seen from the shaftdiameter. The rotation limiting plates (grooves) 9 shown in FIG. 8 arecomparatively simple examples of limiting plates (grooves) 9 in whichthe projecting section 9-1 is at a single location and is narrower thanthe cylinder periphery, being about ¼ of the whole periphery.

FIG. 9 is a model given in explanation of the limiting mechanism in thecase where the rotation limiting mechanism is provided at a singlelocation. The opening/closing shaft 3 comprises a casing 13, a rotationlimiting plate (groove) 9 drawn in FIG. 8, and a projection 3-1 thatsupports the rotation limiting plate 9. In the FIG. 9, the rotary shaft2 is drawn vertically with respect to the paper face and theopening/closing shaft 3 is drawn in the paper face. Hatched section inthe FIG. 9 is the rotation limiting plate 2-3 of the oval-shaped of therotary shaft 2 and it is assembled passing through the opening/closingshaft 3. (a) shows the case where a groove section 9-2 of the rotationlimiting plate 9 drawn in FIG. 8 abuts the long diameter section of thelimiting plate 2-3 on the rotary shaft. (b) shows a case where therotary shaft 2 only has been rotated through 90°, with the limitingplate (groove) 9 left stationary. It can be seen that the rotary shaft 2is not subjected to rotation limitation, since, in the conditions of (a)and (b), the width of the long diameter section that is capable ofrotation is guaranteed. In this embodiment of FIG. 9, this angularposition where the rotary shaft can freely rotate is the position ofFIG. 3(b) and is a position in which the rotary shaft 2 has rotated(opened) by 900 from the start position with respect to theopening/closing shaft 3. FIG. 9(c) shows the case where theopening/closing shaft 3 has been further rotated by 60° from FIG. 9(b).This produces a condition in which rotation cannot take place (thelimitation applies), owing to the action that, the linear sections thatis of the short diameter section of the limiting plate 2-3 of the rotaryshaft 2 and is of the projection 9-1 of the rotation limiting plate 9abut mutually.

FIG. 9 shows an example in which the rotation limiting mechanism isprovided at a single location; however, a constitution in which thearrangement of the two locations on the left and right, further, thelong diameter and short diameter section provided on the rotary shaft 2,and the projection 9-1 and groove 9-2 of the rotation limiting plate 9as set out in the first aspect is reversed could also be adopted. In thethird aspect of the present invention, the rotation of the rotary shaftis restricted depending on the opening/closing shaft's opening angle byuse of parts like the rotation limiting plate 9 as aforementioned,however, embodiments aren't restricted to this, a part that ismonolithically formed with the rotation limiting plate 9 and the casing13 can be used. Here, since the rotation limiting plate 9 movesintegrally with the casing 13 when torque is taken out, that is calledas a drive body with respect to the shat. In this case, the part isformed such that the portion of the rotation limiting plate 9 isconnected with and aperture of the casing 13, and a face that abutsagainst the rotation limiting plate 2-3 of the rotary shaft is providedon a portion of the drive body's aperture.

As embodiments of the first to the third aspects, cases were describedas above in which the rotation limiting mechanism is implemented by therotation limiting plate 2-3 that is in contact with the rotary shaftside 2-2 on the side of the bracket 1. However, in order to reduce sizeand weight, an arrangement could of course be adopted like one in whichrotation limitation is effected by the provision of the rotationlimiting plate 2-3 on the side of the stop ring 2-5.

FIG. 10 is a model given in further explanation of the rotation limitingmechanism of the two-shaft hinge of the present invention. The FIG. 10is drawn, in the form of a strip model, with only the opened out groovesection of the cylindrical rotation limiting plate (groove) 9, whoseformation is comparatively easy. FIG. 10(a) is an example in which therotation limiting mechanism is arranged in two locations on both sidesof the rotary shaft; the example in which the long diameter section ofthe limiting plate 2-3 on the rotary shaft and the groove section 9-2 ofthe rotation limiting plate (groove) 9 can effect abutment at twolocations of 0° and 180°, i.e. rotation of the rotary shaft 2 ispossible at those points, but cannot rotate at other locations, beingsubject to the rotation limitation, is shown. (b) shows an example inwhich the mechanism is provided at a single location, the long diametersection of the limiting plate 2-3 on the rotary shaft and the groovesection 9-2 can effect abutment in a limited angular range of 90° to180°, i.e. rotation of the rotary shaft 2 is possible in this range. (c)shows an example in which the rotation limiting mechanism can beconstituted in a narrow angular interval by assembly with the positionsof the groove sections 9-2 of the rotation limiting plate (groove) 9that are arranged on both sides mutually offset in position. In theexample of (c), rotation of the rotary shaft 2 can be achieved atlimited angles of 0°, 45°, 90°, 135° and 180°.

The shape of the rotation limiting plate 2-3 of the rotary shaft 2 isnot restricted to oval shape, so long as long diameter sections andshort diameter sections can be secured, and could for example even beconstituted by a rectangular shape, cylinder, pin, triangular projectionor gear; furthermore, it would be possible for a long-diameter shape tobe formed at only one shaft diameter of the rotary shaft 2.

The rotation limiting mechanism shown in FIG. 10(b) also has thefunction that, if the opening/closing shaft were to be rotated from thecondition in which the rotary shaft 2 is positioned in a range of 90 to180° i.e. where it is not subject to rotational limitation, and theshort diameter section of the rotary shaft 2 and the rotation limitinggroove section 9-2 face each other diagonally, then, the rotary shaft 2is forcibly rotated to a position where the short diameter section andflat section 9-1 are in abutment, by means of the flat section 9-1 ofthe groove section, immediately after the short diameter (linear)section of the rotary shaft 2 contacts the starting section 9-4 of thegroove section.

The rotation limiting mechanism of the present invention can beconstituted as a through-type two-shaft hinge, without limitationsregarding direction of rotation, angle of commencement of limitation, orangular region of the opening/closing shaft 3.

FIG. 11 shows oval-shaped rotary cams 10-1, 12-1 of the opening/closingshaft 3 employed in the opening/closing torque unit along with a springand an opening/closing casing. The shaft holes 10-3, 12-3 are circularso as to permit rotation when the shaft sections 3-2, 3-8 are inserted.In FIGS. 11(a) and (b), the surface of the rotary cam is substantiallydivided into four, and projections 10-5, 12-5 and recessed faces 10-6,12-6 are formed on the face on the opposite side. Inclined faces areformed at the locations 10-7, 12-7. The oval-shaped periphery of therotary cam, as the componential arrangement is shown in FIG. 1, is fixedby pressing into the side wall of the casing 13-1, so that the torquegenerated by the cam is transmitted to the casing 13.

FIG. 12 shows fixed cams 10-2 and 12-2 that are employed in theopening/closing torque unit of the opening/closing shaft 3 and pairedwith the aforementioned rotary cams. The shaft holes 10-4, 12-4 permitsliding with the shaft sections 3-2, 3-8 in the axial direction, but theshaft holes 10-4, 12-4 are of oval shape so as to rotate in unison withthe shaft sections. In (a) and (b), the side face of the ring-shaped camis substantially divided into four, and projections 10-8, 12-8 andrecesses 10-9, 12-9 are formed on the face on the opposite side.Inclined faces are formed at the locations 10-10, 12-10.

The fixed and rotary cam sets for the opening/closing shaft areassembled with their projecting faces and recessed faces opposite, asshown in FIG. 6 and FIG. 1, so that sliding frictional torque or clickaction (pull-in action) is generated. On the other hand, at the otherfaces of the cams, the cams that are here employed have flat faces inorder to achieve union with the spring or tight abutment with the othercomponents.

On the other hand, FIG. 13 shows a rotary cam 5-1 that is employed inthe rotary torque unit of the rotary shaft 2. The shaft hole 5-3 iscircular in shape so as to permit rotation at the location 2-4 of therotary shaft. On one side face of the cam, there are formed, at fourlocations, circular recesses 5-4 and recesses 5-5 along thecircumference.

FIG. 14 shows a fixed cam 5-2 that is the companion with theaforementioned rotary cam and is employed in the rotary torque unit ofthe rotary shaft 2. The shaft hole 5-6 is capable of sliding movement inthe axial direction when the section 2-4 of the rotary shaft is insertedtherein and has a square shape with the four corners thereof radiussedso that it rotates in unison with the shaft. Circular boss projections5-7 are formed at four locations on the periphery, on one side face ofthe cam.

The fixed and rotary cam sets for the rotary shaft are assembled withprojecting faces and recessed faces opposite each other as shown in FIG.1 so that sliding frictional torque or click action (pull-in action) isgenerated by the relative position of the two cams. Meanwhile, at theother faces of the cams, these cams have flat faces that are employed inthis case in order to achieve tight abutment with the other components.

The cam set of FIG. 11 and FIG. 12 serves as a frictional sliding torquegeneration region when one projection is mated with another projection,and as click action (pull-in action) region when a projection is matedwith a recess. In the case of this cam set, a click action (pull-inaction) is generated every time rotation takes place through 180°. Inthe case of the cam set of FIG. 13 and FIG. 14, a click action (pull-inaction) is generated by mating of circular recesses at four locationsconstituted at intervals of 90° with a boss shaped projection. Thisexample is the two-shaft hinge of claim 7 and it realizes the clickaction as described above. The sliding frictional torque generatingregions and the click action (pull-in action) regions may be of variousdifferent patterns, depending on the size and number of the angularregions along the periphery of the projections and recesses. Also, africtional cam set having no projections or recesses could be assembledand employed.

The above fixed and rotary cams have been described for convenience assingle components but in the present invention, in order to reduce thenumber of components or the size, combined components could be employedin which a cam is formed on part of another component.

FIG. 15 shows an example of the two-shaft hinge of the ninth aspect ofthe present invention in which fixing brackets are added to the hingecomponent of the present invention. Left and right L-shaped brackets15-1, 15-2 are formed with holes 15-3, 15-4 for fixing to the deviceframe using screws or the like. The L-shaped bracket 15-2 may bemanufactured as a multi-function member in common with for example thestop ring 15, fixed frictional plate 14 or casing bottom plate 13-2.Also, any type of bracket 15-1 may be adopted, so long as it is of atype that is capable of supporting and fixing the opening/closing shaft3-6; in this case, an example in which a shaft socket 15-5 is formed onthe bracket 15-1 is shown.

INDUSTRIAL APPLICABILITY

The first, the second and the third aspects of the present inventionshow great benefits in the design of a two-shaft construction in which arotary shaft passes through an opening/closing shaft, in greatlyreducing the number of components and reducing the size of the two-shafthinge. In the prior art product, rotation is possible no matter at whatangle of the opening/closing shaft the rotary shaft is positioned. Incontrast, the present invention limits the possible rotation range ofthe rotary shaft in accordance with the angle of rotation (inclination)of the opening/closing shaft by the provision of the rotation limitingmechanism. For example, the case of a portable terminal device in whicha liquid-crystal screen for a monitor is arranged on a bracket of therotary shaft and a keyboard is arranged on the opening/closing shaft,the benefit that an action can be achieved whereby the monitor can berotated and viewed at an optimum specific position (for example aposition at which the monitor is opened by 90°) is obtained.Furthermore, the rotation limiting mechanism has the great benefit thatthe inconvenience that the keyboard and the monitor of the device maycollide due to rotation of the monitor can be prevented from occurring.

The present invention of the second and the forth has the benefit thatreduction in size and weight can be achieved and assembly can besimplified by concentrating the rotation limiting mechanism and theopening/closing torque generating unit in a single location. Also, fromthe practical viewpoint, space is released on one side of theopening/closing shaft; thus there is the benefit that in this space anarea to install components such as antenna wiring, data wiring, an imagedetection element or camera can be secured.

The fifth aspect of the present invention has the benefits that a highsliding torque and a large click action (pull-in action) can be obtainedby a weak repulsive force provided by a coil spring. Also, sincewell-balanced friction is generated at both ends of the spring, thebenefit that a high durability characteristic can be maintained for along period without one-sided wear of the abutment faces of the rotaryand fixed cams is obtained.

By the present invention of the sixth aspect, it is possible that theangle of rotation of the opening/closing shaft and the rotary shaft isstopped at any desired angle, whereby, stability of the hinge during useof the device can be improved, rattling can be prevented anddurability/strength can be improved as the considerable benefits.

According to the seventh aspect of the present invention, there are thebenefits of maintenance at a specified angle and/or stability of thehinge and improved durability, since it is made possible to produce aclick action (pull-in action) towards a prescribed angle, from within aprescribed angular range.

According to the eighth aspect of the present invention, stableoperation of the fixed cam is ensured and the considerable benefits ofpreventing a shaky feeling or rattling are obtained.

According to the ninth aspect of the present invention, there is thebenefit of an expansion of the range of use of the hinge, by adopting abracket fixing system in the case of a device having a step, or in caseswhere sufficient installation space cannot be secured.

1. A two-shaft hinge that has a rotary shaft and an opening/closingshaft and enables a rotational action and an opening/closing action,wherein, the rotary shaft is inserted into the opening/closing shaft byfitting the rotary shaft into a through hole provided in a verticaldirection with respect to a longitudinal direction of theopening/closing shaft; a fixed cam, a rotary cam and a spring areinserted into each of the rotary shaft and the opening/closing shaft;the fixed cam and the rotary cam abut by the spring force; the abuttingcams and the spring compose a torque unit that independently generates asliding frictional torque at the rotational action and theopening/closing action; a rotational action of the rotary shaft islimited by a rotation limiting mechanism depending on a rotational angleof the opening/closing shaft; and the rotation limiting mechanism limitsthe action by abutting faces to limit at two locations provided betweenthe rotary shaft and the opening/closing shaft.
 2. A two-shaft hingeequipped a rotation limiting mechanism that has a rotary shaft and anopening/closing shaft and enables a rotational action and anopening/closing action, wherein, the rotary shaft is inserted into theopening/closing shaft by fitting the rotary shaft into a through holeprovided in a vertical direction with respect to a longitudinaldirection of the opening/closing shaft; a fixed cam, a rotary cam and aspring are inserted into each of the rotary shaft and theopening/closing shaft; the fixed cam and the rotary cam abut by thespring force; the abutting cams and the spring compose a torque unitthat independently generates a sliding frictional torque at therotational action and the opening/closing action; a rotational action ofthe rotary shaft is limited by a rotation limiting mechanism dependingon a rotational angle of the opening/closing shaft; and the rotationlimiting mechanism limits the action by abutting faces to limit at asingle location provided between the rotary shaft and theopening/closing shaft.
 3. A two-shaft hinge equipped with a rotationlimiting mechanism according to claim 1, wherein, a part of the rotaryshaft has a cross-section which has a long diameter and a shortdiameter, and a width of an aperture thereof has a width such as toobstruct rotation of the rotary shaft while abutting on this crosssection, depending on an angle of opening/closure of the opening/closingshaft and a width such as to make rotation of the rotary shaft possible,or, a rotation limiting groove or a rotation limiting plate is formed inan area on a side of a drive body.
 4. A two-shaft hinge equipped with arotation limiting mechanism according to claim 1, wherein, theopening/closing torque mechanism of the opening/closing shaft isarranged concentrated on one side, either left or right of an axialdirection with respect to the shaft hole of the opening/closing shaftthrough which the rotary shaft passes, while the other side thereofconstitutes a space region for wiring or the like.
 5. A two-shaft hingeequipped with a rotation limiting mechanism according to claim 1,wherein, the opening/closing torque mechanism of the opening/closingshaft comprises units at two or more locations, said units generating africtional torque by a repulsive force of the spring at the abutting camfaces by abutting the rotary cam capable of rotation and the fixed camthat is movable in an axial direction and rotates in unison with theopening/closing shaft and engaging the fixed cam and the rotary camthrough the opening/closing shaft.
 6. A two-shaft hinge equipped with arotation limiting mechanism according to claim 1, wherein a range ofrotation of the rotary shaft and the opening/closing shaft is limited byproviding a stop mechanism for limiting the rotation and theopening/closing angle of the rotary shaft and the opening/closing shaft.7. A two-shaft hinge equipped with a rotation limiting mechanismaccording to claim 1, wherein, in order to generate a click action at aspecified position during the rotational action and the opening/closingaction of the rotary shaft and the opening/closing shaft, a mechanismthat generates a click action is provided by providing a projection andrecess on the fixed and the rotary cam constituted on the shafts forgenerating torque and abutment of the projection and recess of the fixedcam and the rotary cam, or by adding an abutment location of aprojection and recess on the rotary shaft and the opening/closing shaft.8. A two-shaft hinge equipped with a rotation limiting mechanismaccording to claim 1, wherein the rotary shaft and the opening/closingshaft respectively have a cross-section formed to be a cross-sectionother than circular at a sliding location of the fixed cam so that thefixed cam integrally rotates with the shafts while sliding.
 9. Atwo-shaft hinge equipped with a rotation limiting mechanism according toclaim 1, wherein a bracket component is added on the opening/closingshaft so as to dispose and fix the two-shaft hinge to an outer frame,and the hinge is fixed by the bracket.